Need help diagnosing a rough running 1997 Mercedes Benz E320.

CODES:

P0301 - Misfire Cylinder 1
P0306 - Misfire Cylinder 6
P1525 - Camshaft Timing Solenoid
????? - Multiple Cylinder Misfire

I have been doing extensive research onthe mbworld, benzworld and peach parts forums regarding my issue and it seems most roads lead to 3 potential problems here.

1. Camshaft Timing Actuator Magnet (Gold solenoid on the front of the motor - Oil leaks in here and causes bad connections, mine had a lot of it)

2. K40 Relay - A relay with (5) 15 amp fuses and (1) 40 amp fuse on the passenger side of the engine bay. The relays tend to get burned connections or go bad altogether.

3. Camshaft Position Sensor - A sensor that is next to the above mentioned solenoid that also gets full of oil and can go bad.

These are the three things I believe to have drilled it down too. I may still be off.

Things I have done:
* Purchased and installed a used Camshaft position sensor from a junkyard - No change
* Purchase a used K40 Relay from a 96 E320 and didn't install because it is missing (2) of the (5) 15 amp fuse slots and I still have not been able to discover a layout or diagram of what any of these fuses are for.
* Ran Seafoam fuel system cleaner through the fuel system
* Replaced the spark plugs and lower wire boots.

+++ I ALSO KEEP BLOWING MY 40AMP FUSE IN MY K40 RELAY OVER AND OVER AGAIN
+++ The engine toughs rough in park and when driving up to 2000 RPM's...after 2,000 RPM's, the engine seems to run more smoothly.
+++ When I pulled my K40 Relay, none of the connections looked bad or black.
+++ My original, still installed K40 Relay is one digit off of my new K40 Relay - One has an 00 and one has an 02 in the sequence of digits

 

1997 Mercedes Benz E320
VIN: WDBJF55F2VA356429

I have a K40 relay I pulled from a junkyard 1996 E320 that I haven't tried in my car yet. It is missing two of the 5 blue 15 amp fuse slots... Possibly F3 and F5? Not sure what the fuses support on my K40 and what is missing from the junkyard K40.

 

The original relay module (still in car) is 210 540 00 72.

The relay module I pulled from the junkard 96 E320 is 210 540 02 72.

I noticed that the junkyard module was different when I went to swap them in my car, so I have not used it.

My car is still starting first try, the car has never died on me, the car will run and drive, the engine runs rough at idle, the engine runs rough and backfires during acceleration up to 2,000 RPM, after 2,000 RPM the engine seems to run smooth, my 40 AMP fuse in the K40 Relay continues to blow (what is it for?) and I replaced the Camshaft Hall Effect Position Sensor, but did not notice any changes.

 

Update: I found a 97 E320 that is being parted out on Craigslist, he has both the K40 Relay and the camshaft timing solenoid (Y49). Waiting to hear back from him and hopefully from someone on these forums... lol. Am I going in the right direction or just wasting money chasing the wrong problems? Bueller? Anybody?

 

Thanks Plutoe for your help, words and interest, I am just dying to get her running normal... I have the car, the tools, the time, the garage and money for parts, but can't find the specific information I need, so sorry if I sounded impatient. :/ lol

The only reason I wanted to grab the parts off this car was because I still don't know what the problem is. If I grabbed two cheapies and tested to see which one made the difference, I'd buy the new version of that part only.

 

What is the large Maxi Fuse supposed to be if not a 40 amp? There are 5 medium sized 15 amps in a row and then there is a large slot with contact that holds a maxi fuse. It came with a 40 in it when I purchased the car, I assumed that was the correct fuse. Like I said, I haven't been able to find the appropriate fuse designations. I appreciate you looking.

 

So you think the engine (motronic) relay could be the source of my misfire and codes? Do you know of a part number for this relay? I haven't heard of this yet, I'll start doing research.

Did you mean that my car has so many problems or this model and engine have so many problems? Could my problem be the mottronic relay and nothing else? Ugh.

 

UPDATE: I cleared the codes, drove it, then took it to Autozone to have the codes read.

The codes came back:
* P0301 - Cylinder 1 Misfire
* P0306 - Cylinder 6 Misfire
* P0300 - Random Multiple Misfire

My P1525 Code must have been an old, stored code so it seems that my K40 Relay and my Camshaft Timing Solenoid were not an issue.

I realized that cylinders 1 & 6 are run by the same coil pack so I swapped that coilpack with the one from Cyl. 3 & 4 and cleared the codes again. When I began to drive my check engine light came on again.

When I reached Autozone this time, they said my codes were:

* P0303 - Cylinder 3 Misfire
* P0304 - Cylinder 4 Misfire
* P0300 - Random Multiple Misfire

The problem moved with my coil pack, so I replaced my coil pack and then wah-lah. The Benz ran much smoother and faster. The check engine light came on again.

I went to Autozone to have them read the codes. Now, the codes read:

* P0302 - Cylinder 2 Misfire

This misfire has me stumped. This has nothing to do with the bad coil pack and I have all new plugs and lower boots. I pulled my cylinder 2 plug and it was black while the rest looked good. I cleaned and sanded the plug for good contact and swapped it with the plug from cylinder 1 in order to see if the problem moved with the plug. Unfortunately, the problem stayed in cylinder two.

I went to Autozone to have the codes read once more and I am still receiving the P0302 Code indicating that cylinder two is misfiring. I feel the misfire while at idle as well as while driving.

What next steps should I take in diagnosing the cylinder two misfire in my 1997 Mercedes-Benz E320? Can a coil pack that runs two cylinders only go bad on one of them? Are there any other spark related pieces I have not yet replaced that power cylinder two? Should I check fuel injectors next? If so, how? Wouldn't fuel injectors throw a more specific code?

If anybody can help, I'd greatly appreciate it! This thing is so much closer to running normal!

 

I think issues flows around "coils/spark plugs/o2 sensors",

why not replace them all, this will clear your mind about ignition & emission system,,

i assuming you will be fine then...

ZAYED,,

 

I can see the temp (with difficulty) all the pixels are there but its not lit up like the clock on the other side of the cluster. What can I do?

2000 e320 Sedan

 

How can I get them to work.

 

I replaced the next coil and it solved the problem. Thanks!